Gun has attached 223 cal. bbl., also includes a 222 REM Mag Shilen bbl. 204 Ruger, plus 6mm-223 Kreiger bbl.  This is from the Norman Johnson Estate who wrote numerous articles for various outdoor magazines. This gun also includes test targets & bass for each of the calibers. 

Manufacturer Remington , Model Model 700, Class 4 caliber , Class Rifle Set